iron head epoxy repair

360notch generously gifted me a set of loaded, bronze guided 2.02 J heads that are max ported and polished to the extent that there are 2 small windows in one runner. One small 2x2mm hole into valve cover threads (easy, stud it with RTV sealer on threads...) and another area farther in on roof under head bolt boss at the port Y. This one is dicey as it appears to travel up the bolt boss to the bolt face where it has been repaired before but the retorquing of the bolt has compromised it again, pulls oil into that runner from head bolt face. So....I plan to run a 2 part epoxy over both areas inside the runner to hopefully seal them for good. What is the best epoxy to use for a med heat application like this? Can I possibly braze with Muggyweld SSF-6 (56% solver solder, cast iron repaired with this stuff on youtube) These heads look awesome and I'd would love to save them. I'd have to get the proper brazing torch/filler rod for this or just buy the 2-part epoxy. Another option would be to epoxy a hardened cup washer on top of the bolt boss to seal up old repair on top? Professional repair is not an option at moment.
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